Embedded radio frequency identification (RFID) package

ABSTRACT

A radio frequency identification (RFID) device is described. In one or more implementations, the RFID device includes an integrated circuit (IC) die electrically connected to a radio frequency (RF) antenna winding for transmitting electronically stored information via the RF antenna winding. The RFID device also includes a substrate comprising a first core laminated to a second core. The RF antenna winding is routed through the first core and the second core. The first core defines a cavity for retaining the IC die. The cavity is disposed within the RF antenna winding in the first core.

BACKGROUND

Radio frequency identification (RFID) technology generally refers towireless non-contact systems that use radio frequency (RF)electromagnetic fields to transfer data. For example, data can betransmitted from a tag attached to an object. The data can be used toidentify and track the object. Some RFID tags do not require batterypower. For instance, an RFID tag can be powered by an electromagneticfield used to read the tag. Other RFID tags use a local power source andemit electromagnetic radiation at radio frequencies. RFID tags typicallycontain electronically stored information that can be read from adistance (e.g., up to several meters away). RFID tags are used invarious industries. For example, an RFID tag can be attached to anautomobile during production and used to track its progress through anassembly line. Additionally, RFID tags can be used to trackpharmaceuticals (e.g., through a warehouse). Livestock and pets can alsohave RFID tags injected for identifying a particular animal. Further,RFID tags can be attached to clothing, possessions, and so forth.

SUMMARY

A radio frequency identification (RFID) device is described. In one ormore implementations, the RFID device includes an integrated circuit(IC) die electrically connected to a radio frequency (RF) antennawinding for transmitting electronically stored information via the RFantenna winding. The RFID device also includes a substrate comprising afirst core laminated to a second core. The RF antenna winding is routedthrough the first core and the second core. The first core defines acavity for retaining the IC die. The cavity is disposed within the RFantenna winding in the first core.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

DRAWINGS

The Detailed Description is described with reference to the accompanyingfigures. The use of the same reference number in different instances inthe description and the figures may indicate similar or identical items.

FIG. 1 is a partial isometric view illustrating an RFID device includinga first core and a second core laminated together with an RF antennawinding routed through the first and second cores, where the first coredefines a cavity for retaining a die electrically connected to the RFantenna winding so that the die is at least partially embedded insidethe RF antenna winding in accordance with an example embodiment of thepresent disclosure.

FIG. 2 is a cross-sectional side elevation view of the RFID deviceillustrated in FIG. 1.

FIG. 3 is a partial top plan view of the RFID device illustrated in FIG.1.

FIG. 4 is a top plan view of the RFID device illustrated in FIG. 1.

FIG. 5A is a top plan view of a first layer of a substrate for an RFIDdevice, such as the RFID device illustrated in FIG. 1, in accordancewith an example embodiment of the present disclosure.

FIG. 5B is a top plan view of a second layer of a substrate for an RFIDdevice, such as the RFID device illustrated in FIG. 1, in accordancewith an example embodiment of the present disclosure.

FIG. 5C is a top plan view of a third layer of a substrate for an RFIDdevice, such as the RFID device illustrated in FIG. 1, in accordancewith an example embodiment of the present disclosure.

FIG. 5D is a top plan view of a fourth layer of a substrate for an RFIDdevice, such as the RFID device illustrated in FIG. 1, in accordancewith an example embodiment of the present disclosure.

FIG. 6 is a partial cross-sectional side elevation view illustrating asubstrate for an RFID device, such as the RFID device shown in FIG. 1,in accordance with an example embodiment of the present disclosure.

FIG. 7 is a flow diagram illustrating a method for fabricating an RFIDdevice, such as the RFID device shown in FIG. 1, in accordance with anexample embodiment of the present disclosure.

DETAILED DESCRIPTION Overview

RFID tags contain electronically stored information that can be readfrom a distance (e.g., up to several meters away). Data from RFID tagscan be used to identify and track an object. For example, an RFID tagcan be attached to a consumable or disposable item, such as an inkjetcartridge, a container of testing strips for use with a glucose meter,and so forth. In these configurations, the RFID tag can be used toauthenticate an item (e.g., to distinguish a legitimate or original itemfrom a counterfeit or replica item), calibrate equipment (e.g., in thecase of a glucose meter), manage limited use or reuse of an item (e.g.,to prevent reuse of a consumable with a limited lifespan), and so forth.However, it may be difficult to ensure that an RFID tag remains affixedto a particular object and/or is not tampered with. For instance, it maybe difficult to affix an RFID tag to a smooth plastic surface, such asthe wall of a container. It may also be difficult to include a tag withan object having a small form factor without interfering with thefunction of the object. Further, in some instances, environmentalconditions encountered by an object having an affixed RFID tag can bedetrimental to the tag, such as heat encountered by a tagged electroniccomponent, or the like.

Accordingly, techniques are described for providing an RFID packagehaving a low profile and small package thickness (e.g., less than aboutone-half millimeter (0.5 mm) in some embodiments). In embodiments, theRFID package is capable of surviving elevated temperatures, such astemperatures encountered during an injection molding process such as aplastic insert molding process. The RFID package can also be constructedusing low cost fabrication techniques. In some embodiments, the RFIDpackages can withstand temperatures of up to about two hundred andeighty degrees Celsius (280° C.). Thus, the RFID devices can be capableof surviving injection molding. In this manner, an RFID device inaccordance with embodiments of the present disclosure can be moldeddirectly into a plastic object, such as a plastic sidewall of a printercartridge, a container of testing strips, and so forth.

Example Implementations

Referring generally to FIGS. 1 through 6, example RFID devices aredescribed. An embedded die RFID device 100 includes an integratedcircuit (IC) die 102 electrically connected to a radio frequency (RF)antenna winding 104 for transmitting electronically stored information,and a multi-layer substrate 106 comprising a first core 108 laminated toa second core 110. The RF antenna winding 104 is routed through thefirst core 108 and the second core 110. The first core 108 defines acavity 112 for retaining the IC die 102, and the cavity 112 is disposedwithin the RF antenna winding 104 in the first core 108 to form an opencavity in the substrate 106 so that the IC die 102 is at least partiallyembedded inside the RF antenna winding 104.

The RFID device 100 has embedded electronic capabilities, includingmemory for characteristic data storage of information that can be readfrom a distance. Thus, in embodiments, the IC die 102 is configured toelectronically store information using a nonvolatile (NV) memory. Theinformation can include, but is not limited to, identifying informationfor authentication, calibration, and so forth. For instance, the RFIDdevice 100 can include security functionality to verify originalequipment manufacturer (OEM) authenticity for an item an RFID device 100is attached to or disposed within. In some embodiments, the RFID device100 can be configured for simple touch authentication. The RFID device100 can be configured to communicate using a short-range wirelesscommunications protocol, such as a near field communication (NFC)standard. However, NFC is provided by way of example only and is notmeant to be restrictive of the present disclosure. Thus, in otherembodiments, the RFID device 100 can be configured to communicate usingother protocols and standards.

In some embodiments, the RFID device 100 can be powered by anelectromagnetic field used to read information stored on the RFID device100. In other embodiments, the RFID device 100 can include an internalpower source for powering transmission of the information stored on theRFID device 100. For example, the RFID device 100 can include a batterypower source. The first core 108 and/or the second core 110 can compriseglass-reinforced epoxy laminate printed circuit board (PCB) material,such as FR4. In some embodiments, the FR4 material forming the substrate106 can be about four hundred micrometers (400 μm) thick. However, thisthickness is provided by way of example only and is not meant to berestrictive of the present disclosure. Thus, in other embodiments thesubstrate 106 can have a thickness of more or less than four hundredmicrometers (400 μm). However, FR4 is provided by way of example onlyand is not meant to be restrictive of the present disclosure. Thus, inother embodiments, the first core 108 and/or the second core 110 can befabricated using other PCB materials.

In some embodiments, the RF antenna winding 104 comprises four (4)layers of antenna winding to provide an enhanced read range. Forexample, as shown in FIGS. 5A through 5D, the first core 108 cancomprise two layers of antenna winding 114 and 116, and the second core110 can comprise two layers of antenna winding 118 and 120. However,four (4) layers of antenna winding are provided by way of example onlyand are not meant to be restrictive of the present disclosure. Thus, inother embodiments, more than four (4) layers (e.g., five (5) layers, six(6) layers, and so forth) or less than four layers (e.g., two (2)layers, three (3) layers, and so forth) can be used for the RF antennawinding 104. For example, the first core 108 can comprise one layer ofantenna winding, and the second core 110 can also comprise one layer ofantenna winding.

In embodiments of the disclosure, the IC die 102 is encapsulated on thesubstrate 106. For example, the IC die 102 can be encapsulated using anencapsulating material 122 such as an epoxy potting or molding materialused to form an epoxy dome (e.g., in the form of a glob top). Theencapsulating material 122 can be used to “pot” the cavity 112.

Referring now to FIG. 6, a stack up for the substrate 106 is described.As shown, substrate 106 includes first core 108 and second core 110,where the first and second cores are laminated together using an epoxymaterial, such as an epoxy material having pre-impregnated compositefibers (pre-preg) 124. In embodiments of the disclosure, the corematerial of the first core 108 may have a thickness ranging fromapproximately one hundred and eighty one-thousandths of a millimeter(0.180 mm) to two hundred and twenty-five one-thousandths of amillimeter (0.225 mm). The core material of the second core 110 may havea thickness ranging from approximately sixty-five one-thousandths of amillimeter (0.065 mm) to one hundred and five one-thousandths of amillimeter (0.105 mm). The pre-preg 124 may have a thickness rangingfrom approximately five one-hundredths of a millimeter (0.05 mm) toseven one-hundredths of a millimeter (0.07 mm).

Plating copper 126 and a solder mask 128 may be positioned on the firstcore 108, and plating copper 130 and a solder mask 132 may be positionedon the second core 110. The plating copper 126 and/or the plating copper130 may have thicknesses ranging from approximately ten one-thousandthsof a millimeter (0.010 mm) to twenty one-thousandths of a millimeter(0.020 mm), and the solder mask 128 and/or the solder mask 132 may havethicknesses ranging from approximately ten one-thousandths of amillimeter (0.010 mm) to twenty one-thousandths of a millimeter (0.020mm). In some embodiments, the thickness of the substrate 106 may beapproximately eighteen one-thousandths of an inch (0.018 in.), and thedepth of the cavity 112 may be about twenty-five one-hundredths of amillimeter (0.25 mm). However, this stack up is provided by way ofexample only and is not meant to be restrictive of the presentdisclosure. Thus, in other embodiments, materials having varyingthicknesses can be used to form the substrate.

Example Fabrication Process

The following discussion describes example techniques for fabricating anRFID package including a die encapsulated in a cavity formed in a firstcore of a substrate. FIG. 7 depicts a process 700, in an exampleimplementation, for fabricating a semiconductor device, such as theexample embedded die RFID device 100 illustrated in FIGS. 1 through 6and described above.

In the process 700 illustrated, a first core and a second core arelaminated together to form a substrate, where the first core defines acavity for receiving a die, and the first and second cores comprise anRF antenna winding (Block 710). For example, with reference to FIGS. 1through 6, an open cavity 112 can be pre-punched in the first core 108of the substrate 106 for retaining the IC die 102. However, pre-punchingthe cavity 112 is provided by way of example only and is not meant to berestrictive of the present disclosure. Thus, in other embodiments, thecavity 112 can be routed in the first core 108 of the substrate 106. TheRF antenna winding 104 comprises continuous antenna winding routedthrough multiple layers of the RFID device 100. In embodiments, openings(e.g., vias) can be created in the cores to facilitate conductiveconnections between the components of the RFID device 100 (e.g., usingelectroplating materials coated onto the interior surfaces of the vias).For example, vias can be used to connect the layers of antenna winding114, 116, 118, and 120.

Next, the die is attached to the substrate in the cavity formed in thefirst core (Block 720). For instance, with continuing reference to FIGS.1 through 6, the IC die 102 can be attached to the substrate 106 andconnected to the RF antenna winding 104 using chip-on-board (COB)fabrication techniques. For example, the IC die 102 can be die attachedor die mounted to the substrate 106. However, COB fabrication isprovided by way of example only and is not meant to be restrictive ofthe present disclosure. Thus, in other embodiments, the IC die 102 canbe connected to the substrate 106 using solder (e.g., solder pads). Forinstance, the IC die 102 can be connected to the substrate 106 usingsurface-mount technology (SMT). Then, the die is connected to the RFantenna winding (Block 730). For example, with continuing reference toFIGS. 1 through 6, wirebonding can be used to connect the IC die 102 tothe RF antenna winding 104. Next, the die is encapsulated (Block 740).For instance, with continuing reference to FIGS. 1 through 6, the IC die102 and the wires can be encapsulated (e.g., using the encapsulatingmaterial 122). Then, the substrate is singulated to form individual RFIDdevices (Block 750). For example, with continuing reference to FIGS. 1through 6, an RFID device 100 can be formed by punching or sawing chipsfrom a wafer formed with substrate 106 and multiple IC dies 102 disposedin cavities 112 formed in the substrate 106.

CONCLUSION

As used herein, the term “approximately” shall mean approximately and/orexactly with respect to the value or range of values specified. Althoughthe subject matter has been described in language specific to structuralfeatures and/or process operations, it is to be understood that thesubject matter defined in the appended claims is not necessarily limitedto the specific features or acts described above. Rather, the specificfeatures and acts described above are disclosed as example forms ofimplementing the claims.

What is claimed is:
 1. A radio frequency identification (RFID) devicecomprising: an integrated circuit (IC) die electrically connected to aradio frequency (RF) antenna winding for transmitting electronicallystored information via the RF antenna winding; a first core comprising afirst layer of the RF antenna winding, the first core defining a cavityfor retaining the IC die; and a second core comprising a second layer ofthe RF antenna winding, the second core directly laminated to the firstcore so that the RF antenna winding is routed through the first core andthe second core, wherein the cavity is disposed within the RF antennawinding in the first core, the first core and the second core comprisinga substrate.
 2. The RFID device as recited in claim 1, wherein thecavity is pre-punched in the first core before the first core islaminated to the second core to form the substrate.
 3. The RFID deviceas recited in claim 1, further comprising at least one of a consumableitem or a disposable item, wherein the substrate and the IC die aremolded into a sidewall of the at least one of the consumable item or thedisposable item during a plastic insert molding process.
 4. The RFIDdevice as recited in claim 1, wherein at least one of the first core orthe second core comprises at least two layers of winding for the RFantenna winding.
 5. The RFID device as recited in claim 1, wherein theIC die is configured to communicate via the RF antenna winding using anear field communication (NFC) standard.
 6. The RFID device as recitedin claim 1, wherein the IC die is at least one of die attached orsurface mounted to the substrate.
 7. The RFID device as recited in claim1, wherein the IC die is encapsulated on the substrate.
 8. A method offorming a radio frequency identification (RFID) device, the methodcomprising: directly laminating a first core and a second core togetherto form a substrate, the first core comprising a first layer of a radiofrequency (RF) antenna winding, the first core defining a cavity forreceiving an integrated circuit (IC) die, the second core comprising asecond layer of the RF antenna winding, the radio frequency (RF) antennawinding routed through the first core and the second core so that thecavity is disposed within the RF antenna winding in the first core, thefirst core having a thickness ranging from one hundred and eightyone-thousandths of a millimeter (0.180 mm) to two hundred andtwenty-five one-thousandths of a millimeter (0.225 mm), the second corehaving a thickness ranging from sixty-five one-thousandths of amillimeter (0.065 mm) to one hundred and five one-thousandths of amillimeter (0.105 mm); attaching the IC die to the substrate in thecavity defined by the first core; and electrically connecting the IC dieto the RF antenna winding.
 9. The method as recited in claim 8, whereinthe cavity is pre-punched in the first core before the first core islaminated to the second core to form the substrate.
 10. The method asrecited in claim 8, further comprising singulating the substrate to forman RFID device.
 11. The method as recited in claim 10, furthercomprising insert molding the RFID device into a plastic sidewall of atleast one of a consumable item or a disposable item.
 12. The method asrecited in claim 8, wherein at least one of the first core or the secondcore comprises at least two layers of winding for the RF antennawinding.
 13. The method as recited in claim 8, wherein the IC die isconfigured to communicate via the RF antenna winding using a near fieldcommunication (NFC) standard.
 14. The method as recited in claim 8,wherein attaching the IC die to the substrate in the cavity defined bythe first core comprises at least one of die attaching the IC die to thesubstrate or surface mounting the IC die to the substrate.
 15. Themethod as recited in claim 8, further comprising encapsulating the ICdie on the substrate.
 16. An embedded die RFID device comprising: anintegrated circuit (IC) die electrically connected to a radio frequency(RF) antenna winding for transmitting electronically stored informationvia the RF antenna winding; a first core comprising a first layer of theRF antenna winding, the first core defining a cavity for retaining theIC die, the first core having a thickness ranging from one hundred andeighty one-thousandths of a millimeter (0.180 mm) to two hundred andtwenty-five one-thousandths of a millimeter (0.225 mm); and a secondcore comprising a second layer of the RF antenna winding, the secondcore directly laminated to the first core so that the RF antenna windingrouted through the first core and the second core, wherein the cavity isdisposed within the RF antenna winding in the first core, the first coreand the second core comprising a substrate, and the IC die isencapsulated within the substrate, the second core having a thicknessranging from sixty-five one-thousandths of a millimeter (0.065 mm) toone hundred and five one-thousandths of a millimeter (0.105 mm).
 17. Theembedded die RFID device as recited in claim 16, wherein the cavity ispre-punched in the first core before the first core is laminated to thesecond core to form the substrate.
 18. The embedded die RFID device asrecited in claim 16, wherein at least one of the first core or thesecond core comprises at least two layers of winding for the RF antennawinding.
 19. The embedded die RFID device as recited in claim 16,wherein the substrate comprises a thickness of less than or equal to atleast approximately five hundred micrometers (500 μm).
 20. The embeddeddie RFID device as recited in claim 16, wherein the IC die is at leastone of die attached or surface mounted to the substrate.